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©Copyright 1996 Rogue Wave Software

RWTValHashSetIterator<T,H,EQ>

• Synopsis
• Please Note!
• Description
• Persistence
• Example
• Public Constructors
• Public Member Operators
• Public Member Functions

#include<rw/tvhset.h>

RWTValHashSet<T,H,EQ> m;
RWTValHashSetIterator<T,H,EQ> itr(m);

RWTValHashSetIterator is supplied with Tools.h++ 7 to provide an iterator interface to RWTValHashSetIterator that is backward compatible with the container iterators provided in Tools.h++ 6.x.

Iteration over an RWTValHashSet is pseudorandom and dependent on the capacity of the underlying hash table and the hash function being used. The only useable relationship between consecutive elements is that elements which are defined to be equivalent by the equivalence object, EQ, will remain adjacent.

The current item referenced by this iterator is undefined after construction or after a call to reset(). The iterator becomes valid after being advanced with either a pre-increment or an operator().

For both operator++ and operator(), iterating past the last element will return a value equivalent to boolean false. Continued increments will return a value equivalent to false until reset() is called.

None

#include<rw/tvhset.h>

#include<rw/cstring.h>
#include<iostream.h>

struct silly_h{
   unsigned long operator()(const RWCString& x) const
   { return x.length() * (long)x(0); }
};

int main(){
   RWTValHashSet <RWCString, silly_h,equal_to<RWCString> > age;
   RWTValHashSetIterator
     <RWCString, silly_h, equal_to<RWCString > > itr(age);

   age.insert("John");
   age.insert("Steve");
   age.insert("Mark");

//Duplicate insertion rejected
   age.insert("Steve");

   for(;itr();) cout << itr.key() << endl;

   return 0;
}
Program Output (not necessarily in this order)
John
Steve
Mark

RWTValHashSetIterator<T,H,EQ> (RWTValHashSet<T,H,EQ>&h);

Creates an iterator for the hashset h. The iterator begins in an undefined state and must be advanced before the first element will be accessible.

RWBoolean
operator()();

Advances self to the next element. Returns false if the iterator has advanced past the last item in the container and true otherwise.

RWBoolean
operator++();

Advances self to the next element. If the iterator has been reset or just created self will now reference the first element. If, before iteration, self referenced the last value in the multi-set, self will now reference an undefined value and false will be returned. Otherwise, true is returned. Note: no postincrement operator is provided.

RWTValHashSet<T,H,EQ>*
container() const;

Returns a pointer to the collection being iterated over.

T
key() const;

Returns the value currently pointed to by self.

void
reset();
void
reset(RWTValHashSet<T,H,EQ>& h);

Resets the iterator so that after being advanced it will reference the first element of the collection. Using reset() with no argument will reset the iterator on the current container. Supplying a RWTValHashSet to reset() will reset the iterator on that container.